February 18, 2012

Sound Illusion May Have Been Inspiration For Stonehenge

by editor

There have been many theories behind the creation of Stonehenge, including some believing the ancient structure was originally intended to be a monument, a calendar, an observatory, or a place for healing or worship.

Now, an American researcher has proposed yet another theory -- that the legendary 5,000-year-old stone circle in southern England may have been an attempt to mimic or recreate an auditory illusion.

According to LiveScience Senior Writer Stephanie Pappas, the theory was put forth by Steven Waller, a doctoral researcher at Rock Art Acoustics USA and a specialist in the field of archaeoacoustics (the study of the sound-related propertied of ancient locations), Thursday during the annual meeting of the American Association for the Advancement of Science (AAAS) in Vancouver, British Columbia.

Waller's theory goes like this: if people were to witness a pair of pipers playing in a field, they would notice that at certain points, the sound waves from each musician would cancel each other out.

This would create specific points where the sound would be dampened, Pappas said, and according to what Waller told those attending the conference, the pattern of quiet spots may have been the inspiration for Stonehenge.

Telegraph Science Correspondent Nick Collins refers to the sound-based illusion as an "interference pattern," and said that the effect occurred when the two sounds clash. As a result, some individuals would hear a louder noise and some would here a more muffled sound, depending upon their position in relation to the source of the music.

Thus, observers would have noticed the music unexpectedly become quieter at certain points, making it seem as though the music itself "was intermittently being muffled by invisible obstacles as the dancers circled the pipers," Collins said.

"You hear the sound modulating between and loud and quiet," Waller told reporters, including Kerry Sheridan of AFP, during the AAAS meeting in Vancouver. "That would have been a very mysterious phenomenon, totally inexplicable. You would think that two pipers playing would sound louder than one piper but as you walk around it modulates and there are some places where it is almost completely silent."

"So the net result... is this ring of invisible objects, massive objects blocking the sound. And it occurred to me that that is very similar to the structure of Stonehenge," he added.

In order to test his theory, Waller conducted an experiment in which he had students don blindfolds and move around in a circle around two pipes, each of which played the same note.

He then asked them to sketch the field which they thought they had been in, and according to Collins' report, most of them drew a series of pillars they believed would have been responsible for muffling the sound at certain points.

Many of those drawings, the Telegraph reporter said, "resembled the layout of Stonehenge."

"As a result of that auditory illusion and that vision of stones that they could hear but not see, that is why they built Stonehenge," Waller said, according to Sheridan. "They made that vision concrete, so to speak, by actually building the temple."